Electromechanical devices in many different forms have been proposed which provide a coded representation of position, most commonly the angular position of a shaft. In general, such devices incorporate a patterned element and at least as many sensors as there are bits in the code. At least one encoder is known that enters pulses into a counter for representing the angular position of a shaft (Poole, U.S. Pat. No. 2,901,170 issued Aug. 25, 1959) but that device depends upon an elaborate electromechanical structure. The art of shaft-position encoders is highly developed, and yet each known position encoder has its set of limitations, usually entailing complexity, high cost, and unreliability.